Chofeitz Chayim predicted that 25 Years after WW1 there will be WW2.
Furthermore, he predicted that 75 Years later there will be a WW3 and then Moshiach will come.

What do you think about this?

Nothing.

Seriously, enough predictions have been made about when Moshiach will arrive that have passed without his arrival that, for practical purposes, I don’t pay attention to any of them anymore.

I simply await the day of his arrival. If he arrives on the day someone predicted him, then good and well. And if he doesn’t arrive then, then I will await the day he does arrive without worrying about anyone’s “predictions.”

yid1818, I see the number 210 which is the number of years that the Jews worked in mitzraim. It is determined from Yitzchok the difference between ישחק and יצחק. It says כימי צאתינו ממצרים אראנו נפלאות so we see that the final גאולה will be similar to mitzraim.

It says that it is forbidden to count תיפח עצמותיו so how can we count the time when Moshiach will come? Even the Ramban on אשר ברא אלקים לעשות calculates that Moshiach will come in the 5118. The Chasam Sofer explains that this was a suitable time, but we were not worthy of it.
There is a story about someone took along his son and a guest to go to the market in Germany a place called Leipzig. When they started to travel, the son asks how much more do we need to travel? The father gets very upset and tells him, what are you asking me we just got on the wagon. They were traveling a few hours, when the guest was asking the same question. He answered him another hour. The son get upset saying why did you scream at me before when I asked the same question? The father said to him that at that time it was not
appropriate to ask the question. The comparison is obvious that we in the akavta demoshicha so now it become time to ask.

Moshiach is suppose to come unexpected. I think that strengthens the recognizing of a miracle. The Maharal explains that when someone repeats some saying in the name of the sayer will bring the redemption. Hashem wants us to recognize His miracles and give credit for it. When we mention the name of the sayer, we are giving credit to him. So surely we will similarly give credit to Hashem for the redemption.

Where exactly did the Chofetz Chaim, zt”l, write that WWII would start 25 years after WWI and that WWIII would occur 75 years later? In 1930, R. Schwab, zt”l heard him say that he saw a destruction coming even more terrible than WWI but he never wrote or said anything more specific than that. The Biur Halacha was clearly his expressed hope, not his prediction.

Joseph, look at the Klei Yokor in the beginning of Parshas Vaychi that the reason that he was held back from revealing the coming of moshiach because if people know that it won’t be in their time, they become meyaash and forget that they are in galus building fancy houses and thereby extending the time when he will come.